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Size exclusion chromatography and rheology of AB/AB2 hyperbranched polymers

Kunamaneni, Suneel; Buzza, D. Martin A; Parker, David; Feast, W. James


Suneel Kunamaneni

W. James Feast


We report size exclusion chromatography (SEC) and linear shear rheology results for a series of AB/AB2 hyperbranched polyesters. For these samples, the weight average molecular weight Mw was systematically varied from 3000 to 250000 but the spacer length between branch points was kept constant (by fixing the mole fraction of AB2 monomers at 43%). The number density for all the investigated polyesters showed a power law distribution with an exponential cut-off at a characteristic upper cut-off mass Mchar,n(Af) ∼ M-τ x exp(-M/Mchar). When rescaled with respect to Mw, all the individual distributions collapsed onto a universal scaling curve, indicating that the molecular weight distribution for short chain branched hyperbranched polymers obeys static scaling with t and the ratio Mchar/Mw, independent of the extent of reaction. We find τ = 1.53 ± 0.05 which surprisingly is the same as the mean field value of 1.5 within experimental error. The dynamic rheological data was modelled using a dynamic scaling theory for unentangled polymeric fractals (based on the Rouse model) and excellent agreement was found. This indicates that these hyperbranched polymers are essentially unentangled. We also demonstrate that rheology is sensitive to rather subtle features of the molecular weight distribution. This means that it can be a useful tool for characterising the molecular weight distribution of branched polymers when used in conjunction with size exclusion chromatography.

Journal Article Type Conference Paper
Publication Date Nov 1, 2003
Journal Journal of Materials Chemistry
Print ISSN 0959-9428
Electronic ISSN 1364-5501
Publisher Royal Society of Chemistry
Peer Reviewed Peer Reviewed
Volume 13
Issue 11
Pages 2749-2755
APA6 Citation Kunamaneni, S., Buzza, D. M. A., Parker, D., & Feast, W. J. (2003). Size exclusion chromatography and rheology of AB/AB2 hyperbranched polymers. Journal of materials chemistry, 13(11), 2749-2755. doi:10.1039/b303473a
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